A wireless communication system typically includes a base station in wireless communication with a plurality of user devices (which may also be referred to as mobile stations, subscriber units, access terminals, user equipment, etc.). The base station transmits data to the user devices over a radio frequency (RF) communication channel. The term “downlink” refers to transmission from a base station to a user device, while the term “uplink” refers to transmission from a user device to a base station.
Orthogonal frequency division multiplexing (OFDM) is a modulation and multiple-access technique whereby the transmission band of a communication channel is divided into a number of equally spaced sub-bands. A sub-carrier carrying a portion of the user information is transmitted in each sub-band, and every sub-carrier is orthogonal with every other sub-carrier. Sub-carriers are sometimes referred to as “tones.” OFDM enables the creation of a very flexible system architecture that can be used efficiently for a wide range of services, including voice and data. OFDM is sometimes referred to as discrete multitone transmission (DMT).
Reference signals are transmitted with data signals in a transmission time interval signal (TTI) in order to demodulate the data. Multiple signals sent from multiple mobile stations cause interference with each other and may cause errors in the demodulation of the data. As such, benefits may be realized from systems and methods for transmitting the transmission time interval signal with staggered reference signals.